CHICAGO - Japanese researchers have found that some strains of influenza notably the type B flu viruses are beginning to demonstrate resistance to two commonly used anti-viral drugs. The details appear in the Journal of the American Medical Association.
Researchers at the University of Tokyo said they had only concentrated on type B viruses and hence their information was limited to this type. Type B viruses are known to cause smaller epidemics than type A viruses. The researchers examined Tamiflu and Relenza in the study.
The former made by Roche happens to be the drug of choice in H5N1 type of influenza as well as seasonal flu. The researchers collected samples from 74 children before and after they received Tamiflu. These samples were compared with 348 normal samples.
The researchers found one sample had reduced drug sensitivity among the 74 samples, while seven of the 422 influenza B viruses demonstrated decreased sensitivity to both Tamiflu and Relenza.
"Continued surveillance for the emergence or spread of neuraminidase inhibitor-resistant influenza viruses is critically important," the authors concluded. "Further evaluation of the biological properties of neuraminidase inhibitor-resistant influenza viruses is needed to fully assess their pathogenicity in humans."
